<div dir="ltr"><div>Dear Mr. Paulo, Mr. Rachid, and Gate Users, </div>Thanks for your quick replies. <div> I'm sorry but I don't really know if my environment variables are set and how to check it. I followed the step called: "update your environment variables file'' in Gate installation guide ( <a href="http://wiki.opengatecollaboration.org/index.php/Compilation_Instructions_V7.1">http://wiki.opengatecollaboration.org/index.php/Compilation_Instructions_V7.1</a> ) which is these two commands: source ~/geant4/geant4.10.01.p03-install/bin/geant4.sh source ~/geant4/geant4.10.01.p03-install/bin/geant4.csh But you can see in my attached pictures, there was an error with the geant4.csh file bash: /home/manhcam0510/geant4/geant4.10.01.p03-install/bin/geant4.csh: line 27: syntax error near unexpected token `(' bash: /home/manhcam0510/geant4/geant4.10.01.p03-install/bin/geant4.csh: line 27: `set ARGS=($_)' And after I tried 3 steps suggested by Mr. Paulo, the error was still the same as yesterday ("no such file or directory" with the geant4make.sh file) and I couldn't run the example. Can you tell me more clearly how to set my environment variables. Thank you very much Manh Cam. </div></div>